The variable trust has become widely used in the social science research lately and few concepts seem to have attracted so much attention from such a broad variety of academic disciplines. In political science in the theories on social capital and political culture, emphasizing its importance for democracy, trus has been seen as na essential variable for the understanding of societies. In social capital theory the generalized interpersonal trust is often given a particularly important role to initiate virtuous circles of development in the societies. This paper will treat some of the different theories that are connected both to the definition and the effects of generalized trust and then issues connected to the uncertainty of the measurements of generalized trust